Efficient electrophilic and nucleophilic epoxidations utilizing a sulfonylperoxy radical and peroxysulfate species
作者:Min Young Park、Seung Gak Yang、Yong Hae Kim
DOI:10.1002/hc.10078
日期:——
((TBA)2S2O8, 2) was prepared by the reaction of tetrabutylammonium hydrogen sulfate with potassium peroxydisulfate. The epoxidation of enals and enones, such as α,β-unsaturated aldehydes or ketones, was efficiently achieved with 2 in the presence of hydrogenperoxide and base in acetonitrile or in methanol at 25°C. A base-sensitive substrate, such as cinnamaldehyde, could be successfully epoxidized under
catalyst containing a tetradentate ligand derived from triazacyclononane exhibits high catalytic activity in epoxidation reactions using peracetic acid as oxidant. The system exhibits broad substrate scope and requires small (0.1-0.15 mol %) catalyst loading. The catalyst is remarkably selective toward aliphatic cis-olefins. Mechanistic studies point toward an electrophilic oxidant delivering the oxygen
A series of trinuclear manganese complexes coordinated with neutral bidentate nitrogenligands, [Mn3L2(OAc)6], were prepared from manganese acetate and the corresponding ligands. Using peracetic acid as the oxidant, the air- and moisture-stable manganese clusters exhibited excellent catalytic activity and selectivity in the epoxidation of olefins under mild conditions. The highest activity was observed
由乙酸锰和相应的配体制备了一系列与中性双齿氮配体[Mn 3 L 2(OAc)6 ]配合的三核锰配合物。使用过氧乙酸作为氧化剂,空气和水分稳定的锰簇在温和的条件下在烯烃的环氧化中表现出出色的催化活性和选择性。用含有2-吡啶基配体[Mn 3(ppei)2(OAc)6的三核配合物观察到最高的活性。](ppei = 2-吡啶-1-苯基乙亚胺)。使用该系统,底物范围非常广泛,可以包括脂肪族和芳香族烯烃的末端和电子缺陷双键。即使直接使用吡啶基吡啶基配体和乙酸锰的混合物在反应条件下也不会降低高活性,这使该方法更方便。还观察到类似的三核络合物,例如[Mn 3(bipy)2(OAc)6 ]和[Mn 3(phen)2(OAc)6],表现出色。从产物分布中可以推断出自由基的中介性,动力学数据表明,在锰簇簇前体和氧化剂中,环氧化分别大致为一级,而在烯烃中则为零级。这些结果导致我们提出三核配合物[Mn 3 L 2(OAc)6
Amino-acid-mediated epoxidation of α,β-unsaturated ketones by hydrogen peroxide in aqueous media
作者:Juhyun Kim、Suhyun Jung、Sojung Park、Seongsoon Park
DOI:10.1016/j.tetlet.2011.03.115
日期:2011.6
Amino acids, such as arginine and lysine, can be used as an efficient catalyst in the epoxidation of α,β-unsaturated ketones with aqueoushydrogenperoxide. Up to >99% conversion was obtained in the reaction toward 11 α,β-unsaturated ketones.
Epoxy–amine oligomers from terpenes with applications in synergistic antifungal treatments
作者:Dara M. O’Brien、Cindy Vallieres、Cameron Alexander、Steven M. Howdle、Robert A. Stockman、Simon V. Avery
DOI:10.1039/c9tb00878k
日期:——
Epoxy–amine oligomers synthesised from a renewable terpenoid feedstock are found to act in synergy with known antifungal drug amphotericin B against Candida albicans, and fungicide IPBC against Trichoderma virens.